1. Field of the Invention
The present invention relates to a hydrogen energy supply system using ocean current power generation, and more particularly to a novel and breakthrough hydrogen energy supply system using ocean current power generation that uses ocean currents to generate electric power, applies electrolysis to seawater with the use of generated electrical energy to produce hydrogen energy, and supplies the produced hydrogen energy to a consumer side as liquid hydrogen.
2. Description of the Related Art
Approximately 70% of solar energy applied to the earth falls onto the sea, and this solar energy is mainly converted into kinetic energy of ocean currents and present.
In case of generating electric power using such kinetic energy of the ocean currents, since power generation energy is proportionate to the third power of a flow velocity of ocean currents, a location with the highest flow velocity of ocean currents must be selected as a power generating location.
That is, as the power generating location, a distant sea area rather than the vicinity of land is often selected.
To transmit electrical energy generated in such a sea area to the land, a long-distance power transmission system is required, its construction costs are high, and long-distance power transmission results in considerable transmission loss of the electrical energy.
That is, in case of performing long-distance transmission of electric power generated by many (e.g., 100 to 10000) power generators in a sea area distant from land, electric power generated by each power generator must be adjusted by a frequency conversion device before transmission so that the same frequency can be provided, the electric power must be boosted to a high voltage (10000 volts to 100000 volts) to minimize the transmission loss, and a power transmission line must be newly laid to transmit the power.
In addition, it is known that the transmission loss is lowered as a transmission voltage is increased. For example, it is known that decupling the transmission voltage from 100 V to 1000 V results in reducing the transmission loss to 1/100.
However, adoption of the above-described system leads to various kinds of non-negligible power loss, e.g., loss at the time of frequency adjustment, transmission loss due to long-distance power transmission, or loss caused when power is discarded without being consumed during the night.
Further, although storing generated electrical energy in a power accumulation equipment can be considered, a large-capacity storage battery is required, and high costs must be put in, which is not cost effective.
In patent Literature 1, proposed is a hydrogen production plant that uses natural energy of, e.g., tidal currents to generate electric power, uses this generated electric power to produce a hydrogen gas from seawater with the use of movable seawater electrolytic hydrogen production device, performs liquefaction by a hydrogen liquefaction device, stores a resultant substance as liquid hydrogen in a liquid hydrogen storage tank, and transmits the liquid hydrogen to consumers by a transporting tanker (Patent Literature 1: FIG. 3).
However, in case of the hydrogen production plant according to Patent Literature 1, when a power generator is installed below a movable berth and the liquid hydrogen production plant is placed on this berth, the number of power generators to be installed is small and electric power generation of these power generators is small with respect to entire production costs including the berth, and a floor area or the like required for the seawater electrolysis device using this generated power and liquid hydrogen production and storage is overabundant. Consequently, an increase in hydrogen gas production costs and in liquid hydrogen transmission costs is inevitable.
[Patent Literature 1] Japanese Unexamined Patent Application Publication No. 2003-72675